7.9kg正方体铁块静止于1m^2的水瓶桌面中央,求铁块对桌面的压强.(取铁的密度=7.9g/cm^3,g=10N/kg)
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![7.9kg正方体铁块静止于1m^2的水瓶桌面中央,求铁块对桌面的压强.(取铁的密度=7.9g/cm^3,g=10N/kg)](/uploads/image/z/1524027-3-7.jpg?t=7.9kg%E6%AD%A3%E6%96%B9%E4%BD%93%E9%93%81%E5%9D%97%E9%9D%99%E6%AD%A2%E4%BA%8E1m%5E2%E7%9A%84%E6%B0%B4%E7%93%B6%E6%A1%8C%E9%9D%A2%E4%B8%AD%E5%A4%AE%2C%E6%B1%82%E9%93%81%E5%9D%97%E5%AF%B9%E6%A1%8C%E9%9D%A2%E7%9A%84%E5%8E%8B%E5%BC%BA.%EF%BC%88%E5%8F%96%E9%93%81%E7%9A%84%E5%AF%86%E5%BA%A6%3D7.9g%2Fcm%5E3%2Cg%3D10N%2Fkg%EF%BC%89)
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7.9kg正方体铁块静止于1m^2的水瓶桌面中央,求铁块对桌面的压强.(取铁的密度=7.9g/cm^3,g=10N/kg)
7.9kg正方体铁块静止于1m^2的水瓶桌面中央,求铁块对桌面的压强.(取铁的密度=7.9g/cm^3,g=10N/kg)
7.9kg正方体铁块静止于1m^2的水瓶桌面中央,求铁块对桌面的压强.(取铁的密度=7.9g/cm^3,g=10N/kg)
V=m/密度=7.9/(7.9×10^3)=1×10^-3m^2
h=三次根号v=三次根号1×10^-3m^2=0.1m
s=h^2=0.1×0.1=0.01m^2
0.01小于1
所以S=0.01m^2
P=F/S=G/S=mg/S=7.9×9.8/0.01=7742pa
答:压强为7742pa
79n
先计算出正方体的体积,V=m/ρ=1000cm³,其中边长L=10cm,受力面积s=100cm²,压强P=F/s=G/L²=mg/L²=7.9×10^5N。
v=m/密度=10^-3
s=0.01
p=f/s=79/0.01
=7900pa